Soil penetration testing and sampling device for use in deep drill holes



March 15, 1955 E. D. RHOADES SOIL PENETRATION TESTING AND SAMPLING DEVICE FOR USE IN DEEP DRILL HOLES Filed June 13, 1951 INVENTOR EA PLE 7. /FHofs B Y f/ 1. 5 ATTORNEY United States Patent SOIL PENETRATION TESTING AND SAMPLING DEVICE FOR USE IN DEEP DRILL HOLES Earle D. Rhoades, Coulee City, Wash.

Application June 13, 1951, Serial No. 231,418

2 Claims. (Cl. Z55-1.4)

(Granted under Title 35, U. S. Code (1952), scc. 266) The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon in accordance with the provisions of the act of April 30, 1928 (Ch. 460, 45 Stat. L. 467).

This invention relates to a soil testing device and more particularly it relates to a soil penetration testing and sampling device for use in deep drill holes.

It has been common practice to attempt to obtain samples of soil from a drill hole at substantial depths below the ground surface. Prior to this invention these samples were obtained by digging test pits, by drive sampling using either single or double core barrels, or by the use of highly complicated and expensive equipment. These methods are expensive, slow and not too well adapted for deep hole work. The data obtained from these tests usually reflects increased density and changed cohesion values in the soil sample due to the driving force and friction between the soil and the penetrating instrument in these instruments.

An object of this invention is to provide a device which will give a more accurate indication of the characteristics of the strata from which a soil sample is taken.

An additional object of the invention is to provide a device which will give a more accurate indication of the plasticity of natural soils than drive sampling or hammer penetration devices.

A further object of the invention is to provide a device which permits thick strata to be penetration tested, followed by undisturbed sampling of penetrated and adjacent natural soils.

A more specific object of the invention is to provide a device which will avoid the need for digging costly test pits to the desired depths for determination of soil properties in advance of the design or construction of final drilling structures.

Another object of vthe invention is to provide a device which can be used on a standard drilling machine without moditications to the machine, which device is capable of making penetration tests and securing samples at the proper rate of speed, accurately controlled.

Additional objects will be obvious from a consideration of a particular embodiment of the invention and of the drawing wherein:

Figure 1 is an elevation, partially cut away, of an embodiment of the invention.

Figure 2 is an elevation of an intermediate portion of the device of Fig. l showing the manner in which extending sections of the apparatus may be joined.

Figure 3 is a longitudinal sectional view of a modiiication in which a detachable soil sampler is provided at the bottom end of the pressure rod.

The objects of this invention are accomplished by a device which comprises drive means which are adapted to be secured in the chuck of a drilling machine, a drive rod which is connected to said drive means and is selectively operable to engage the drive means and to be fed downward by it, a pressure cell adapted to transmit the force of the drive rod, suiiicient pressure rods attached to the pressure cell to extend to the bottom of the drill hole, and a sampler attached to the end pressure rod.

In a particular embodiment of the invention and referring now to the drawing, there is shown a drive means for the sampling device. As shown in Figure 1, the drive means 1.0 consists of a drive nut, the end 11 2,704,202 Patented Mar. 15, 1955 lCe of which is secured in the rotating chuck of a drilling machine (not shown). This drive nut in the embodiment illustrated is provided with internal lefthanded threads.

Threaded into the drive nut 10 is a drive rod 12. The upper portion of drive rod 12 is also threaded at 13 and these external threads are also lefthanded in the ligure to allow the rod to be screwed into the drive nut 10. It is obvious that these devices may be threaded either righthanded or lefthanded so long as they are threaded the same and cooperate as hereinafter described. The opposite end 14 of the drive rod 12 is seated on the upper portion of the pressure cell 15.

Pressure cell 15, as shown in the drawing, is constructed of two circular plates 16, 16A, separated by and bolted to a ring 17 to form a at, circular, tight receptacle. The cell is filled with any suitable uid capable of transmitting pressure. Light machine oil has been found quite suitable for the purpose of this invention.

Connected to the pressure cell 15 and communicating with the fluid chamber is a pressure gauge 18 which is calibrated to indicate the pressure of the uid in the cell. Mounted on the upper and lower plates 16, 16A of the pressure cell 15 are suitable seats 19, 19A for the end114 of drive rod 12 and pressure rod 20, respective y.

The pressure rod 20 may be made up of a number of extensions or sections similar in structure, the bottom section of which is provided with a detachable soil sampler, which may consist of a penetration needle 24 as shown in Fig. l, or of a device 24a as shown in Fig. 3 which will obtain a plug of soil to be brought to the surface. The soil sampler is attached to the bottom rod section by any suitable means, such as by stud 25, which slcrews into a cooperating female iitting in the rod as s own.

Pressure rod 20 is preferably shielded from contactwith the walls of the bore hole by the provision of an outer concentric tubular rod 21 which may also be made up in sections, joined, for example, by screw-type couplings 26 as shown in Fig. 2. The outer tubular rod 21 may be lowered into the well bore independently of the pressure rod 20, or, alternatively, sections of the outer rod containing a corresponding length of inner rod are screwed into the rods already in the hole and inner and outer rods are lowered together. The inner rod sections may be provided with screw-type fittings 27 which cooperate with studs 28 to connect those sections. ln order to hold theV inner and outer rod sections together and facilitate the assemblage of these parts, a bolt 29 through the rods may be provided. A slot 30 in the inner rod section accommodates bolt 29 and permits sufficient axial movement of the inner rod string with respect to the outer rod for penetration and sampling at the bottom of the hole. The invention, however, is not limited to the use of concentric rods nor the use of the exterior rod as such a shield. The string may be formed of single rods if desired, and the soil sampler attached to the end thereof.

In the operation of applicants device to obtain a soil sample each of the elements of the apparatus from the upper drive rod 12 to the sampling device 24a exclusive of the outer tubing are weighed. The pressure cell gauge 18 is calibrated to establish the value in pounds per square inch for each division of the gauge.

The soil sampler 24a is then attached to the bottom section of the bottom pressure rod 20. Enough additional pressure rods with or without shielding sections are successively added to permit lowering the string of rods to the bottom of the hole and the penetration needle or sampler then rests upon the material to be tested. Pressure rod 20 is then attached to the bottom of pressure cell 15 by mount 19A. The drive nut 10 is then put into the chuck of the drill machine and held in place by the chuck jaws. The upper drive rod 12 is then screwed into the drive rod nut 10 for its entire threaded length and is then connected to the upper surface of the pressure cell 15 by means of mount 19.

The chuck is then rotated in the usual righthand manner if lefthanded threads have been used. The upper drive rod 12 is then prevented from rotating by any suitable means, for example, by hand if the size of the device permits. As the rotation of the drive nut 10 continues while the rotation of drive rod 12 has been stopped, these two parts being lefthandedly threaded, the upper drive rod 12 feeds downwardly.

This downward motion of drive rod 12 exerts a pressure on the pressure cell 15 which registers on gauge 18 and which pressure is transmitted through the cell to rods 20 and hence acts to drive the soil sampler 24a into the material to be sampled or tested,

The weight of the pressure rods and other elements of the assembly is added to the registered pressure ot the gauge to establish the pressure required to penetrate the material being tested.

It will be appreciated from a reading of the foregoing specification that the invention herein described is susceptible of various changes and modifications without departing from the spirit and scope thereof. The invention is, therefore, to be limited only by the scope and spirit as set forth in the appended claims.

What is claimed is:

l. A soil testing device comprising an internally threaded drive nut adapted to be secured in and rotated by a drill chuck, an externally threaded drive rod which isV adpted'v'to be threaded into said drive nut, a pressure cell including a pair of spaced, flexible metal plates enclosing a hydraulic chamber, means providing a seat for an end of said drive rod on the upper one of said metal plates, a Vpressure gauge communicatingly connected to said"hydrau1ic chamber to measure the hydraulic pressure therein, a pressure rod extending from the lower one of said metal plates to the bottom of a drill hole, and a soil sampler attached to the end of said pressure rod, whereby the driving force from said drive rod to said pressure rod and soil sampler is measurable as a hydraulic pressure created by the action of said flexible metal plates upon the uid in the hydraulic chamber of the pressure cell.

2. A soil testing device comprising a drive nut adapted to be secured in and rotated by a drill chuck, a drive rod threadedly engaging said drive nut and selectively operable to be fed downward by the rotation of said drive nut, a pressure cell engaging the end of said drive rod and operable to hydraulically transmit the downward force thereof, a pressure gauge communicatingly connected to said pressure cell for measuring the pressure transmitted thereby, a pressure rod extending from said pressure cell, and a soil sampler attached to the end of said pressure rod and adapted to be driven into the soil whereby upon rotation of the drive nut by the drill chuck a driving force is transmitted through the drive rod, pressure cell, and pressure rod to the soil sampler.

References Cited in the tile of this patent UNITED STATES PATENTS 2,128,833 Martin Aug. 30, 1938 2,309,211 Raphael Jan. 26, 1943 FOREIGN PATENTS 43,095 Holland May 16, 1938 260,507 Switzerland Aug. 1, 1949 

